1. Field of the Invention
This invention relates to couplers for trailers and the like. More particularly, the invention relates to a coupler wherein a cap is automatically closed when a ball is placed within the ball cavity of the coupler.
2. Description of the Prior Art
Jacob, in U.S. Pat. Nos. 1,927,591 and 1,977,065, issued Sept. 19, 1933 and Oct. 16, 1934, respectively, discloses a trailer hitch in which a body and cap are hinged at a front portion and form hemispherically shaped cavities for enclosing a coupling ball. A collar is spring biased in a forward position on a rear portion of the body and releasably latches the cap in a closed position around the ball. In the later Jacob patent, a boss is formed on the body on the parting face and the cap has a corresponding recess which fits over the boss when the cap is closed to the body. The cap has a tapered side surface against which the collar bears for a snug fit of the cap around the ball. The spring biased collar rides up on the tapered surface so that the collar automatically adjusts the cap for slight variations in a given ball size and for wear between the ball and the cavity and socket therefor.
In the U.S. Pat. No. 3,759,549 issued to Morris on Sept. 18, 1973, a compression spring is placed to the rear of the ball cavity and operably connected between the body and rear portion of the cap. The compression spring automatically pushes open the cap which is hinged in the front to the body. A rotatable locking sleeve has an offset recess which limits the opening movement of the cap.
The U.S. Pat. No. 3,880,450 issued to Ware on Apr. 29, 1975 discloses and claims a coupler having a body and cap hinged together at the front portion. The body forms the major portion of the ball cavity and includes a ball centering upper surface of the cavity forming a self-centering bearing surface for the ball. One of the body or cap has a tapered rearwardly extending surface which a collar engages and latches the cap to the body.